1. Field of the Invention
The invention relates to an exit light and an emergency light which have function to indicate residual charge of a battery.
2. Description of the Related Art
An exit light and an emergency light are escape apparatuses which last for 60 minutes when a building experiences a fire and a power outage. A storage battery is generally used as an energy source of the escape apparatus to sustain for a certain period of time.
When the storage battery is aged and out, the exit light and the emergency light cannot perform for a certain period of time. Therefore, how well the storage battery is charged is important for the operation of the escape apparatus.
Conventionally, it was necessary to turn off the general exit light and emergency light for a certain period of time to check the residual charge of battery thereof. However, it requires quite a long time to check batteries of many exit lights and emergency lights, and availability of the lights for operation is hardly evaluated after the check.
To solve the problems, users do not turn off the exit light and emergency light but operate check switch to determine the state of exit light and emergency light.
However, even if the check switch indicates no malfunction sign, it does not guarantee that exit light and emergency light will maintain for a certain period of time.
In operation, the check switch of the exit light and emergency light indicates through green LED the state of utilized power supply, and charged or discharged state through red LED, but the check switch does not indicate the residual charge of the battery.
Manufacturers can check the abnormality of the general exit light and emergency light, but users cannot check the residual charge of the battery.